Naysayers have already pointed out that uptake of Facebook email could be slow - no one really wants to abandon an established email address, and everyone already has email. Several users have pointed out that even if they do sign up for a Facebook address, they'll just configure it to automatically forward to Gmail, Yahoo!, or whatever other mail client they happen to prefer.

I think this misses the point. What Facebook cares about here isn't so much eyeballs - they already have those. What they want/need is more information about you and your friends. So what if you forward that email out of Facebook to another mail client? The content still exists inside Facebook, so Facebook can potentially leverage that data to drive the ads they show when you log in to update your status - even if you never lay a hand on their email offering.

I'm also not so sure adoption will be scant; remember the land rush that happened when Facebook released vanity URLs? Do you really want someone else squatting on myname@facebook.com? You'll claim that email address just to keep someone else from getting it. And this is assuming that Facebook doesn't just assign an email address to everyone based on their existing user ID. Either way, once the email is established, the data can start flowing. As this post from Business Insider points out, even if only 1/3 of US Facebook users start using Facebook mail, Facebook will still be the second most popular email provider in the States (http://www.businessinsider.com/chart-of-the-day-email-sites-2010-11).

Facebook has time - email isn't a focus, it's an enhancement. And so far, Facebook seems to be encroaching on Google more than Google's managed to encroach on Facebook. There's a reason that Microsoft has cozied up to Facebook; this game isn't about Google vs Microsoft; it's about Facebook vs Google. If you can't beat someone going toe-to-toe, better to be friends with the one who looks to have an edge.

Well, the Facebook Messaging announcement is complete. This isn't about just Facebook email - it's much more. Here are a few of my observations.

• This notion of seamless integration between SMS, IM, Email, and Facebook messages is interesting. By throwing these disparate message types into a single bucket, Facebook is trying to give us a good reason to start using their solution. That said, I'm not sure how useful a non-subject-threaded, single-stream-per-contact Inbox will be. I can see iteration coming in this area.
• The facebook.com domain will be for Facebook users' email addresses; Facebook corporate will move to the fb.com domain. Per my earlier speculation about the land rush - Facebook will give anyone who wants one an email address on the facebook.com domain based on your Facebook user account ID. Still not clear if this will be opt-in or opt-out. Based on past Facebook experience, I'm guessing opt-out. Update 11/16/2010: Based on early screen caps from Mashable, you will have the option to opt-in to a @facebook.com email address when setting up your new Facebook Messages Inbox. 
• The project took more than a year and had a team of 15 engineers plus support staff - the largest project yet at Facebook. Clearly this is a focus.
• Zuckerburg went to great pains to claim that this is about 'embrace, not replace' [my words, not his]. "This is not an email killer," Zuckerburg stated. Like I said in my earlier post, they've got time to grow into this; they're not asking anyone to throw anything away today. They don't need to - see my comments below.
• A reporter asked directly about advertising. Zuckerburg claimed that they would not show advertising based on the content of messages. I'm guessing this has to be true, in the same way that Google doesn't display advertising based on the content of your Gmail.

The most insightful observation was one that both Zuckerburg and the on-stage PM clearly sidestepped, even though it was mentioned 3 separate times. That is: with the new Facebook messaging, emails you receive from non-Facebook users will become a part of the social graph. This is significant. In the same way that the Like/Recommend social widgets made the greater Web a part of the social graph, Facebook Messaging extends the reach of Facebook into the conversations you have with individuals who have no interest in social networks. It's just one more way that Facebook continues to thread their tendrils through the fabric of the web. How will Google answer this? All I know is that Facebook has rapidly upped the ante in the last couple of months, and the answer coming out of Google HQ had better be pretty compelling.

Will you start using Facebook Messaging right away? Sounds like it's going to be invitation-only for the first while, then rolled out to everyone over the next few months. Leave a comment and give me your thoughts. Be sure you choose the option to post your comment on Facebook - it's all going to be a part of the social graph, anyway...